!-------------------------------------------------------------LICENSE--------------------------------------------------------------!
!                                                                                                                                  !
!The MAP code is written in Fortran language for magnetohydrodynamics (MHD) calculation with the adaptive mesh refinement (AMR)    !
!and Message Passing Interface (MPI) parallelization.                                                                              !
!                                                                                                                                  !
!Copyright (C) 2012                                                                                                                !
!Ronglin Jiang                                                                                                                     !
!rljiang@ssc.net.cn                                                                                                                !
!585 Guoshoujing Road. Pudong, Shanghai, P.R.C. 201203                                                                             !
!                                                                                                                                  !
!This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License         !
!as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.             !
!                                                                                                                                  !
!This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of    !
!MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.                        !
!                                                                                                                                  !
!You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software     !
!Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.                                                   !
!                                                                                                                                  !
!-------------------------------------------------------------LICENSE--------------------------------------------------------------!

!==================================================================================================================================|
subroutine bnd_user(ro, mx, my, mz, bx, by, bz, en, gx, gy, gz, po,                                                                &
                    ro0, mx0, my0, mz0, bx0, by0, bz0, en0,                                                                        &
                    x, y, z, nx, ny, nz, ng, dir, sides)
!==================================================================================================================================|
!  sides = 'l' for lower boundary
!  sides = 'h' for higher boundary
!  sides = 'b' for both
!----------------------------------------------------------------------------------------------------------------------------------|

   implicit none

   character(1), intent(in) ::  dir, sides
   integer(4), intent(in) :: nx, ny, nz, ng
   real(8), intent(in) :: x(nx), y(ny), z(nz)
   real(8), dimension(nx, ny, nz), intent(inout) :: ro, mx, my, mz, bx, by, bz, en, gx, gy, gz, po
   real(8), dimension(nx, ny, nz), intent(in) :: ro0, mx0, my0, mz0, bx0, by0, bz0, en0

!----------------------------------------------------------------------------------------------------------------------------------|
   if (dir .eq. 'x') then
      if (sides .eq. 'l') then
         
      endif
      if (sides .eq. 'h') then

      endif
      if (sides .eq. 'b') then

      endif
   elseif (dir .eq. 'y') then
      if (sides .eq. 'l') then

      endif
      if (sides .eq. 'h') then

      endif
      if (sides .eq. 'b') then

      endif
   elseif (dir .eq. 'z') then
      if (sides .eq. 'l') then

      endif
      if (sides .eq. 'h') then

      endif
      if (sides .eq. 'b') then

      endif
   else
      write (*, *) 'Direction error from bnd_user.'
      stop
   endif

!----------------------------------------------------------------------------------------------------------------------------------|
   return
end subroutine bnd_user
